Cost-reduced torque converter shrouds

ABSTRACT

A method of manufacturing an annular transmission component for a vehicle includes providing a tube defining an annular wall having a predetermined diameter. The tube is cut to a form a tube blank having a first end and a second end. The tube blank placed into a forming machine and the first end of the tube blank is rolled relative to the second end of the tube blank forming an annular U-shaped channel defined between the first and the second end.

PRIOR APPLICATIONS

The present application claims priority to U. S. Provisional Patent Application No. 62/051,604 filed Sep. 17, 2014.

TECHNICAL FIELD

The present invention relates generally toward a method of forming an annular component. More specifically, the present invention relates toward forming an annular component of a mechanical device from a tube.

BACKGROUND

Various annular elements have been included in transmissions for vehicles and other devices for many years. These annular, or ring-link, components have always been formed in a progressive die having up to 16 forming stages for stamping sheet metal into a desirable annular configuration. The waste associated with manufacturing an annular component is astronomical because sheet metal disposed central to the annular component, in addition to the sheet metal disposed exterior to the annular component, becomes waste material that must be processed and transferred to recycling center at great cost. Upwards of 75% of the original sheet metal becomes waste material.

In addition, the dies and presses associated with a progressive manufacturing process costs hundreds of thousands of dollars and are difficult to maintain and operate. Modifying these dies to accommodate die changes, due to their complexity, is also exceedingly expensive. Still further, due to the high number of forming steps, manufacturers have been unable to use high strength steel when forming the annular component, which would allow for reduced thickness providing a lower weight component. Therefore, there is a long-felt need for identifying a low-cost alternative to progressively forming an annular housing, such as, for example, a torque converter shroud or other annular transmission component.

SUMMARY

A tube defining an annular wall having a predetermined diameter is provided for manufacturing an annular transmission component for a vehicle. The tube is cut to form a tube blank having a first end and a second end. The tube blank is placed into a forming machine and rolled so that the first end of the tube blank forms an annular u-shaped channel with the second end of the tube blank.

The process of the present invention eliminates complex progressive dies and stamping machines by requiring only a single forming machine to reshape a tube blank into a desired configuration of a torque converter or other annular transmission housing. Furthermore, scrap and waste material is nearly completely eliminated by forming the annular component from a tube, which reduces significantly the cost of manufacturing the annular component. An additional benefit is that high strength steel may now be used to form the annular component because only a single forming stage is required, which allows for a reduced material thickness providing a lower weight component.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detail description when considered in connection with the accompanying drawings.

FIG. 1 shows a perspective view of a torque converter shroud;

FIG. 2 shows a perspective view of a tube blank;

FIG. 3 shows a tube blank disposed in a forming machine; and

FIG. 4 shows the forming machine pressing the tube blank into an annular component.

DETAILED DESCRIPTION

Referring to FIG. 1, a shroud for a torque converter is generally shown at 10. While “shroud 10” will be used throughout this specification, should be understood to those of ordinary skill in the art that a shroud 10 is merely exemplary and that the present method of forming an annular transmission component can be used on any annular component of a power train or transmission of a motorized device. The shroud 10 includes a first end 12 and a second end 14 separated by a u-shaped wall 16. A plurality of slots 18 are formed in the u-shaped wall 16. The slots, as should be known to those of ordinary skill in the art, extends circumferentially around the u-shaped wall 16 and are designed to receive fins (now shown) when, in this embodiment, a torque converter (not shown) is completely assembled.

Referring now to FIG. 2, a tube blank 20 is cut from a tube or pipe to a predetermined length. As such, the first end 12 and a second end 14 are defined by the tube blank 20. The tube blank 20 defines an annular wall 22. A seam 24 extends from the first end 12 to the second end 14. The seam 24 is formed from welding sheet stock that is rolled into a tubular formation in a known manner from a pipe manufacturing process. Alternatively, the seam 24 can be formed from a mechanical joint or joined with epoxy or other adhesive. In a still further embodiment, the tube blank 20 is seamless having a drawn over mandrel configuration. In one embodiment, the tube blank 20 is formed from high strength low alloy (HSLA) steel. Alternatively, the tube blank 20 is formed from high-carbon steel, high strength aluminum, or high strength composite depending on a particular application and requisite mechanical properties.

Unique to this method of forming an annular component is that HSLA steel even selectable as a substrate. The use of HSLA or other high strength material is not possible when a progressive forming process is used due to the work hardening of the material that occurs with each forming stage. High strength steel is known to fracture in latter stages of a progressive process due to resultant work hardening. This is not a concern when a single forming step is used as described further herein below.

An additional benefit to the inventive method of the present application is the ability, for the first time, to align a grain 25 of the steal in an axial a direction. The process by which the tube, and ultimately the tube blank 20 is formed aligns the grain 25 of the metal in a single direction that is parallel to the axis a of the tube. Forming the shroud 10 by rolling the second end 14 in a radial direction maintains the alignment of the grain 25 in the axial a direction. Alignment of the grain in the axial direction provides improved strength over an un-aligned grain, which is characteristic of a progressive stamping process beginning with sheet metal. With the improved strength, the thickness of the shroud 10 can be decreased providing mass and additional cost savings.

Referring now to FIGS. 3 and 4, the inventive forming machine of the present application is generally shown at 26. In this example, the forming machine 26 is represented as a die press. However, it should be understood to those of ordinary skill in the art that alternative forming machines may be used to shape the tubular blank 20, including a roll former, and an orbit-forming machine. An upper die member 28 and a lower die member 30 are disposed in a press 32. The upper die member 28 includes a punch 34 that is sized to form an inner diameter of the shroud 10 defined by the first end 12. A form ring 36 is defined by the upper die member 28 is configured to roll the second end 14 of the tube blank 20 to define the u-shaped wall 16.

The lower die 30 defines an annular post 38 that is complementary with the form ring 36 over which the tube blank 20 is rolled to define the shroud 10. For expediency, a shroud 10 and the blank at 20 are both shown in FIG. 3.

During the forming, the tube blank 20 is inserted into the forming machine 26 and placed upon a support 40 so that the tube blank 20 and forming ring 36 define a common axis a. The upper die member 28 is actuated by way of gravitational, hydraulic pressure, or servo motor to form the tube blank 20 into the shroud 10 configuration. The punch 34 extends inwardly of the now forming shroud 10 to define the inner diameter of the shroud 10. The second end 14 of the shroud 10 is disposed radially outwardly of the first end 12 and is either allowed to float freely during forming, or abut a stop 42 to verify accurate location of the second end 14. FIG. 4 shows the upper die member 28 completely actuated to mate with the lower die member 30 forming the shroud 10.

In a single step, a shroud 10 is formed by the forming machine 26 and requires no further operation to provide accurate dimensional configuration. In some instances, slots 18 are formed in the annular wall 22. Alternately, notches 45 are formed in either the first end 12 or the second end 14 and extend circumferentially around the entire first end 12 or second end 14. It should be further understood that a larger diameter tube blank 20 may be placed on the lower die member 30 and the first end 12 is rolled radially inwardly from the second end 14 to achieve a similar, or same, configuration with a shroud 10. Still further, either the first end 12 or the second end 14 can extend in the axial a direction relative to the other end so that the u-shaped wall 16 more closely represents a j-shaped wall.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The foregoing invention has been described in accordance with the relevant legal standards; thus, the description is merely exemplary than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and do come within the scope of this invention. Accordingly, the scope of a legal protection afforded this invention can only be determined by studying the following claims. 

1-14. (canceled)
 15. A method of making an annular transmission component for a vehicle, the method comprising: placing a tube blank having first and second ends into a forming machine; and rolling the first end of the tube blank radially and axially relative to the second end thereby forming an annular, arcuate shaped channel between the first end and the second end.
 16. The method of claim 15, wherein rolling the first end of the tube blank includes rolling the first end radially outward.
 17. The method of claim 15, wherein rolling the first end of the tube blank includes rolling the first end radially inward.
 18. The method of claim 15, wherein the forming machine comprises at least one of a roll former, a die press, and an orbit forming machine.
 19. The method of claim 15, wherein the tube blank comprises at least one of a high strength steel, a high-carbon steel, HSLA steel, or a high strength composite.
 20. The method of claim 15, wherein after the rolling the first end has a first circumference and the second end has a second, different circumference.
 21. The method of claim 20, wherein a difference between the first circumference and the second circumference corresponds to a length of the tube blank between the first end and the second end.
 22. The method of claim 21, comprising selecting the tube blank to have the length between the first end and the second end for forming the U-shaped channel with a desired surface length between the first end and the second end and the difference between the first circumference and the second circumference.
 23. The method of claim 15, comprising using the forming machine for establishing notches along an edge at the first end or the second end.
 24. The method of claim 15, comprising using the forming machine for establishing slots in a wall of the arcuate shaped channel.
 23. The method of claim 15, wherein the tube blank includes a seam extending axially along the tube blank between the first end and the second end.
 24. The method of claim 23, comprising establishing the seam by at least one of welding edges of material of the tube, mechanically interlocking the edges of the material of the tube, and gluing the edges of material of the tube.
 25. The method of claim 15, wherein the tube blank has a metal grain having an alignment with an axial direction from the first end to the second end; and rolling the first end comprises maintaining the alignment of the metal grain from the first end to the second end.
 26. The method of claim 15, wherein the first end and the second end have an initial diameter and the method comprises supporting the second end in the forming machine to maintain the initial diameter of the second end during the rolling; and changing the diameter of the first end during the rolling.
 27. The method of claim 15, wherein rolling the first end comprises moving the first end into a position relative to the second end where the first end and the second end are in a single plane and the arcuate channel is a U-shaped channel.
 28. The method of claim 15, wherein rolling the first end comprises moving the first end into a position relative to the second end where the first end and the second end are in separate planes and the arcuate channel is a J-shaped channel.
 29. The method of claim 15, wherein the rolling is accomplished during a single movement of a die member of the forming machine.
 30. A method of making an annular shroud, the method comprising: situating a tube in a forming machine, the tube having a first end, a second end and an annular wall of a generally constant initial diameter between the first end and the second end; roll forming the tube to cause the first end of the tube to have a different diameter than the initial diameter and to shape the annular wall to have an arcuate shape between the first end and the second end; and supporting the second end in the forming machine to maintain the initial diameter near the second end.
 31. The method of claim 30, wherein roll forming the tube comprises rolling the first end radially and axially relative to the second end.
 32. The method of claim 30, wherein the roll forming is accomplished during a single movement of a die member of the forming machine.
 33. The method of claim 30, wherein the tube has a metal grain having an alignment with an axial direction from the first end to the second end; and the roll forming comprises maintaining the alignment of the metal grain from the first end to the second end.
 34. The method of claim 30, wherein the different diameter of the first end is larger than the initial diameter. 